Oh man, I feel this in my bones. I spent way too long eyeballing my mix too, till a patio I did in Denver turned into a crumbly mess after one wet winter. Now I use a cheap digital scale and it's night and day. It's not even about being fancy, it's just that the joints hold up way better and I don't have to guess why something failed. Yeah, it adds a few minutes, but I'd rather do that than redo the whole damn job.

and honestly that reminds me of the time I grabbed a cheap digital thermometer for my classroom aquarium and it said the water was 95 degrees when it was room temp, so I spent a whole weekend convinced my fish were boiling. point is, sometimes the budget gear does more harm than good cause you end up second guessing everything instead of just trusting the reading. I still have that thermometer in a drawer somewhere, but I never use it now, just like that gauge probably sits in a box too.